Setting bouncing curve in graph editor
Short answer: Not much.
The amplitude is simply whatever time you let between the two keyframes. But you can't edit anything else.
I'd recommend making your own bounces anyway. Unless you just need a quick and dirty solution and don't have much expectations, doing it manually is simpler, and it's not hard to do.
I like to make a first arc, set the apex key to Autoclamped interpolation if it isn't already (use the V shortcut), and the low keys to Vector.
Then I duplicate this arc as many times I want, and I adjust the height of the curve. Scale the apex keys to adjust the timing, and use Free vectors if you really need fine-tuning frame by frame.